/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jasper.security;

import org.apache.jasper.Constants;

/**
 * Util class for Security related operations.
 * 
 * @author Jean-Francois Arcand
 */

public final class SecurityUtil {

	private static boolean packageDefinitionEnabled = System
			.getProperty("package.definition") == null ? false : true;

	/**
	 * Return the <code>SecurityManager</code> only if Security is enabled AND
	 * package protection mechanism is enabled.
	 */
	public static boolean isPackageProtectionEnabled() {
		if (packageDefinitionEnabled && Constants.IS_SECURITY_ENABLED) {
			return true;
		}
		return false;
	}

	/**
	 * Filter the specified message string for characters that are sensitive in
	 * HTML. This avoids potential attacks caused by including JavaScript codes
	 * in the request URL that is often reported in error messages.
	 * 
	 * @param message
	 *            The message string to be filtered
	 */
	public static String filter(String message) {

		if (message == null)
			return (null);

		char content[] = new char[message.length()];
		message.getChars(0, message.length(), content, 0);
		StringBuffer result = new StringBuffer(content.length + 50);
		for (int i = 0; i < content.length; i++) {
			switch (content[i]) {
			case '<':
				result.append("&lt;");
				break;
			case '>':
				result.append("&gt;");
				break;
			case '&':
				result.append("&amp;");
				break;
			case '"':
				result.append("&quot;");
				break;
			default:
				result.append(content[i]);
			}
		}
		return (result.toString());

	}

}
